Bat with maraging steel shell

ABSTRACT

A bat includes a bat frame and an outer sleeve. The bat frame has a barrel portion, a tapered transition portion, and a handle portion. The bat frame is preferably constructed of aluminum material. The outer sleeve is constructed of a maraging steel material and is received over the barrel portion of the frame. The outer sleeve preferably includes a tapered proximal end which is received in a nesting engagement with the tapered transition portion of the bat frame.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates generally to the construction of bats for baseball and softball, and more particularly, but not by way of limitation, to such a bat with a two-piece construction including an aluminum bat frame and an outer shell constructed of a maraging steel material for improved bat performance.

[0003] 2. Description of the Prior Art

[0004] Over the years, the technology for construction of high performance bats for baseball and softball has advanced from the original solid wooden bat, to a tubular aluminum bat, and subsequently to various composite bats, and to bats having an outer shell over the barrel of a bat frame in order to combine the durability and performance characteristics of hard, high strength materials, with the desired flexibility in the bat frame and lightweight provided by materials such as aluminum.

[0005] One such example of such a bat having a bat frame with an outer shell is that found in U.S. Pat. Nos. 6,053,828 and 6,159,116, assigned to the Assignee of the present invention, the details of which are incorporated herein by reference. The aforementioned patents disclose a bat having an aluminum outer shell received about an aluminum bat frame.

[0006] Another example of a high performance bat having an outer shell of a different material than the bat frame is the bat currently marketed by Worth, Inc., the Assignee of the present invention, as its PST™ bat, which utilizes an aluminum bat frame and an outer shell constructed from a powder metallurgy technology, the outer shell including a titanium material.

[0007] Previous bats having titanium outer shells on an aluminum bat frame are found in Japanese Patent No. 5-57042 to Susumu.

[0008] Bats including titanium outer shells are also disclosed in Abkowitz, U.S. Pat. No. 6,143,429.

[0009] Thus, it is seen that there is a continuing demand in the industry for advanced technology high performance bat constructions.

SUMMARY OF THE INVENTION

[0010] The present invention provides a bat having a frame and an outer sleeve. The frame has a barrel portion, a tapered transition portion and a handle portion. The outer sleeve is received over the barrel portion of the frame, and is constructed of a maraging steel material.

[0011] The outer sleeve preferably has a tapered proximal end which is received over and is in nesting engagement with the tapered portion of the bat frame. An adhesive material is provided between the bat frame and the outer sleeve, and a mechanical press is preferably used to press the bat frame and outer sleeve into engagement to form a permanent attachment therebetween.

[0012] Preferred dimensional ranges are provided for the aluminum bat frame and the maraging steel outer shell.

[0013] Preferred protective corrosion-resistant coatings and processes are disclosed for the maraging steel outer shell.

[0014] The maraging steel outer shell is preferably constructed from a maraging steel alloy selected from the group of alloys consisting of T-200 Maraging Steel, T-250 Maraging steel, C-250 Maraging Steel, C-300 Maraging Steel or C-350 Maraging Steel.

[0015] Accordingly, it is an object of the present invention to provide an improved bat construction.

[0016] Another object of the present invention is the provision of a bat structure including a maraging steel hitting surface.

[0017] Still another object of the present invention is the provision of a bat construction having an aluminum bat frame and a maraging steel outer shell attached to the bat frame.

[0018] And another object of the present invention is the provision of improved methods for construction of a bat having a maraging steel hitting surface.

[0019] Another object of the present invention is the provision of suitable protective coatings and material treatment processes for reducing corrosion of the maraging steel outer shell.

[0020] Still another object of the present invention is the provision of an improved construction for a high performance ball bat.

[0021] Other and further objects, features and advantages of the present invention will be readily apparent to those skilled in the art upon a reading of the following disclosure when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1 is a side view of a bat constructed in accordance with the present invention.

[0023]FIG. 2 is a sectioned side view of the bat of FIG. 1.

[0024]FIG. 3 is a somewhat schematic illustration of the manner in which the bat of FIG. 1 is assembled.

[0025]FIG. 4 is an enlarged sectioned side view of the left hand end of the bat of FIG. 2.

[0026]FIG. 5 is an enlarged sectioned view of the outer shell of the bat.

[0027]FIG. 6 is a still further enlarged view of the right hand end of the bat shell of FIG. 5.

[0028]FIG. 7 is a still further enlarged sectioned view of an intermediate portion of the bat of FIG. 2 showing the nesting relationship between the proximal end of the outer shell and a part of the tapered transition portion of the bat frame.

[0029]FIG. 8 illustrates the preferred dimensions of one example of the bat frame and outer sleeve, when viewed in conjunction with Tables II and III set forth below.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Referring now to the drawings, and particularly to FIG. 1, the bat of the present invention is shown and generally designated by the numeral 10.

[0031] The bat 10 includes a bat frame 12, an outer sleeve 14, and an end plug 16.

[0032] As best seen in FIG. 2, the bat frame 12 includes a barrel portion 18, a tapered transition portion 20, and a handle portion 22.

[0033] The bat 10 is assembled in the manner schematically illustrated in FIG. 3.

[0034] The shell 14 having a straight open distal end 24 and a conically tapered proximal end 26 is provided. As further described below, the shell 14 is constructed of a maraging steel material.

[0035] The bat frame 14 is constructed in a conventional manner by forming the same from a cylindrical tube of aluminum material An adhesive material, preferably a two part polyurethane liquid adhesive, will be placed on either the inner surface of the shell 14, or the outer surface of the barrel 18 and part of the tapered section 20 of frame 12 in the zone indicated by 28, or both, and then the shell 14 will slide over the handle portion 22 of bat frame 12 and into nesting engagement with the bat frame 12 as seen in FIGS. 2 and 7.

[0036] Preferably, this assembly step will be accomplished by locking the outer shell 14 into a mold (not shown) and then pushing the bat frame 12 through the outer shell and into nesting engagement with the outer shell, said pushing being accomplished by mechanical means, such as a hydraulic piston (not shown). This can be described as pressing the outer shell 14 into nesting engagement with the bat frame 20 by means of a mechanical press (not shown).

[0037] The combination of the adhesive and the use of a hydraulic press to assemble the bat frame 12 and outer shell 14 make it virtually impossible to remove the shell 14 from the bat frame 12.

[0038] After this assembly, the end plug 16 is snapped into place as shown in FIG. 4, and a knob 30 is welded onto the handle portion 22 of bat frame 12. End plug 16 has two first annular lip 31 engaging the distal end 33 of frame 12, and second annular lip 35 engaging distal end 24 of shell 14.

[0039] Then, various finishing steps may be applied to improve the cosmetic and performance characteristics of the bat.

[0040] Particularly, when using a maraging steel outer shell, it is important to provide either protective coatings or protective treatments to provide corrosion resistance of the maraging steel outer shell 14.

[0041] Suitable protective coatings to provide corrosion resistance of the maraging steel outer shell 14 include poly urethane, epoxy, acrylic paint, electro static acrylic powder coating or other barrier films.

[0042] Suitable protective treatments to improve the corrosion resistance of the maraging steel outer shell include electro-plating and electrochemical techniques (cathode protection).

The Maraging Steel Outer Shell

[0043] The preferred material for the construction of the outer shell 14 is a maraging steel. Maraging steels are a specific group of high nickel (i.e. greater than 10% nickel), low carbon martensitic steels which can be fabricated while in a comparatively ductile martensitic condition and later strengthened by aging treatment.

[0044] The following description of the general category of maraging steels is taken from the background section of U.S. Pat. No. 6,136,102, the details of which are incorporated herein by reference:

[0045] “Maraging steels are self-tempering steels which can acquire a soft martensitic structure by cooling in air, which structure can be appreciably hardened by a thermal aging treatment which gives rise to formation of intermetallic precipitates. In essence, these steels contain:

[0046] 10-30 wt. % nickel, which enables one to obtain a martensitic structure by cooling in air;

[0047] a low carbon content which enables one to obtain a soft martensite; and

[0048] additional elements which enable hardening by formation of intermetallic precipitates, said elements being namely titanium, aluminum, and molybdenum, as well as cobalt, where the presence of the cobalt enhances the effects of the other added elements.

[0049] One may also add niobium, to fix the carbon and thereby soften the un-aged martensitic structure.

[0050] These steels were devised in the face of the problem of simultaneously obtaining a very high limit of elasticity and good ductility. Initially, good ductility was obtained by simultaneous addition of cobalt and molybdenum.

[0051] However, cobalt as an alloying element is costly and not available from a reliable source of supply. In order to avoid the constraints imposed by cobalt, maraging steels without cobalt were developed which contain:

[0052] Ni 17-26 wt. %, Mo 0.2-4 wt. %, Ti 1-2.5 wt. %,

[0053] A1<1 wt. %, and optionally some Nb,

[0054]  with the remainder being Fe and impurities resulting from the processing. Such steels are described, e.g., in Brit. Pat. 1,355,475 and U.S. Pat. No. 4,443,254; both incorporated herein by reference. They enable one to obtain a high tensile strength (on the order of 1800 MPa) and satisfactory ductility, in a metal which is homogenized at elevated temperature followed by cooling and aging.”

[0055] One preferred manner of forming the maraging steel outer shell is the use of flow forming processes, such as those available from Dynamic Machine Works, Inc. of Billerica, Mass. Particular materials available from Dynamic Machine Works, Inc. which are suitable for use in the present invention are their T-350 Maraging Steel (aged 900° F.), C-300 Maraging Steel (aged 900° F.), and their C-350 Maraging Steel (aged 900° F.). The material properties of these three particular maraging steel alloys available from Dynamic Machine Works, Inc. after flow forming are set forth in the following Table I. TABLE I .2% Wall Yield, Material Reduction KSI UTS, KSI Elongation T-250 Maraging Steel 75% 286.00 292.00 5.00 (aged 900 F.) C-300 Maraging Steel 55% 295.00 306.00 7.50 (aged 900 F.) C-350 Maraging Steel 71% 382.46 388.86 2.10 (aged 900 F.)

[0056] Flow forming is a process wherein a tubular article is formed by the application of both axial and radial forces through a series of rollers controlled by a computer. A cylindrical maraging steel starter tube is formed by plastic deformation into the desired final shape of the outer shell 14 by rotating the starter tube while engaging it with the rollers which cause the maraging steel material to be flow formed into the desired final shape.

[0057] In general, the maraging steel materials used to construct the outer shell 14 may be selected from the group of maraging steel alloys consisting of the following: T-200, T-250, C-250, C-300 and C-350.

EXAMPLE

[0058] One embodiment of the bat of the present invention utilizes a bat frame 12 and outer shell 14 having the dimensions as set forth in FIG. 8.

[0059] In general, the maraging steel outer shell 14 preferably has a wall thickness in the range of from about 0.025″ to about 0.045″, whereas the bat frame 12 constructed of aluminum material has a wall thickness in the range of from about 0.040″ to about 0.060″.

[0060] The aluminum material from which the bat frame 12 is constructed may be of any of the following aluminum materials or alloys: 7050, 7055, C555, 7049, 7149, 7046, PA95, PA100, CU31, or C405.

[0061] It is also within the contemplation of the present invention to construct a one piece bat, that is a bat without an outer shell, wherein the bat itself is constructed of a maraging steel material.

[0062] Thus, it is seen that the apparatus and methods of the present invention readily achieve the ends and advantages mentioned as well as those inherent therein. While certain preferred embodiments of the invention have been illustrated and described for purposes of the present disclosure, numerous changes in the arrangement and construction of parts and steps may be made by those skilled in the art, which changes are encompassed within the scope and spirit of the present invention as defined by the appended claims. 

1. A bat, comprising: a frame having a barrel portion, a tapered transition portion, and a handle portion; and an outer sleeve received over the barrel portion of the frame, the sleeve being constructed of a maraging steel.
 2. The bat of claim 1, wherein the maraging steel outer sleeve is formed by a flowforming process.
 3. The bat of claim 1, wherein the maraging steel is selected from the group of alloys consisting of C-350 Maraging Steel, C-300 Maraging Steel, C-250 Maraging Steel, T-200 Maraging Steel, and T-250 Maraging Steel.
 4. The bat of claim 1, wherein the maraging steel outer sleeve has a wall thickness in the range of from about 0.025″ to about 0.045″.
 5. The bat of claim 4, wherein the bat frame is constructed of an aluminum material, and the barrel portion of the bat frame has a wall thickness in the range of from about 0.040″ to about 0.060″.
 6. The bat of claim 1, further comprising a protective corrosion resistant coating on the exterior of the maraging steel outer shell.
 7. The bat of claim 6, wherein the protective corrosion resistant coating comprises acrylic powder coating.
 8. The bat of claim 6, wherein the maraging steel out shell has been treated to improve the corrosion resistance of the shell.
 9. The bat of claim 1, wherein: the maraging steel outer shell includes a tapered end that nests about a part of the tapered portion of the frame.
 10. The bat of claim 1, further comprising: an adhesive between the bat frame and the maraging steel outer shell.
 11. The bat of claim 10, wherein: the adhesive is a two-part urethane adhesive.
 12. The bat of claim 1, further comprising: an annular end cap having a first annular lip engaging a distal end of the bat frame, and having a second annular lip engaging a distal end of the maraging steel outer shell.
 13. A bat, comprising: a barrel portion, a handle portion, and a tapered transition portion between the barrel portion and the handle portion; and wherein the barrel portion includes a hitting surface including a maraging steel material.
 14. The bat of claim 13, wherein: the maraging steel material is an alloy selected from the group of alloys consisting of C-350, C-300, C-250, T-250 and T-200 Maraging Steels.
 15. A method of constructing a bat, comprising: (a) providing a bat frame having a barrel portion, a tapered transition portion, and a handle portion; (b) providing an outer shell including a maraging steel material; (c) securely attaching the outer shell to the bat frame so that the outer shell extends over at least a majority of the barrel portion of the bat frame.
 16. The method of claim 15, wherein: in step (b), the outer shell includes a tapered proximal end; and further comprising the step between steps (b) and (c), of sliding a distal end of the outer shell over the handle portion of the bat frame and engaging the tapered proximal end of the outer shell in a nesting engagement with the tapered transition portion of the bat frame.
 17. The method of claim 16, further comprising: pressing the outer shell into said nesting engagement by means of a mechanical press.
 18. The method of claim 17, wherein the pressing step comprises: locking the outer shell into a mold; and pushing the bat frame through the outer shell and into said nesting engagement, said pushing being accomplished by mechanical means.
 19. The method of claim 15, further comprising: applying a corrosion resistant coating over the outer shell.
 20. The method of claim 15, further comprising: treating the outer shell by to make the outer shell more corrosion resistant.
 21. The method of claim 15, wherein: the bat frame is constructed of an aluminum material, the barrel portion of which has a wall thickness in the range of from about 0.040″ to about 0.060″ inch; and the maraging steel outer shell has a wall thickness in the range from about 0.025″ to about 0.045″. 